Modern cars allow entry using a key fob, and some cars allow starting by a button when the key fob is inside the car. Such operation is called passive entry and passive start, which use a position of the key fob to unlock the car, allow starting the car, and provide other functionality. The location of the key fob is determined using magnetic signals emitted from magnetic antennas in the car. The magnetic signals are measured by the key fob and sent to the car for determining a location of the key fob.
The key fob can be bulky and be an additional item that a user must carry. Further, the magnetic fields are short range, and current techniques are susceptible to hackers, which can allow a thief to access the car and potentially steal it.
Therefore, it is desirable to provide new methods and devices that overcome any one of these problems.